Absorption refrigerating machine



July 9, 1929. w EY 1,720,160

ABSORPTION REFRIGERATING MACHINE Filed June 25, 1923 In 2) e1 1 117123111 ".1 the absorbing liquid used with it.

Patented July 9, I i

UNITED. srATEs ELIAS WIBT H-FRCEY, OF A ARAU, SWITZERLAND.

" momma REFRIGERATING MACHINE.

Application filed Julie 25, 1923, Serial No.

This invention relates'to'im'provements in refrigerating machines orapparatus of the absorption type.

It is known that refrigerating machines of 5 this class workingintermittently by means of a generator-absorber are particularlysuitedfor household purposes and for similar se on a small scale, owingto the fact that no gas compressor or pumps are required inv con- 1nection therewith. q

The great drawback inmachines 0f-this kind as hitherto constructed isthat the evaporator gradually becomes filled with a residue consistingof the cooling agent and In the generating operation part of the lessvolatile absorbing liquid naturally passes over together with the morevolatile cooling agent, and this results in theevaporator containing aconstantlyincreasing amount of residual liquor. Inconsequence of theincreasing proportion of absorbing. liquid therein, the vapour pressure,is reduiied and this liquor I consequently fails to evaporate at theabsorp- D tion-pressures at whichthe apparatus works.

Gradually therefore, the evaporator becomes filled'up with residualliquor, and theexchan e of heatbetween the evaporator and the asorbermay eventually stop entirely.

Attempts have been made to obviate this defect by interposing anauxiliary cooler between the generator and the condenser and condensingmainly the evaporated absorbent therein. If, in spite of this, some ofthe absorbin liguid passes into the evaporator, it

must e \either by means of suitable piping and valves, an operationwhich involves a certain amount of attendance and the provision offittings, or 40 by heating the evaporator externally in order @to raiseits temperature, thereby ing the residual liquor to evaporate.

Butmeans ofthis kind are not admissible in small refrigerating machineswhich are usually attended by servants. On the contrary,it is imperativeto construct themso as to operate automatically.

The object of the present invention is to provide an automaticrefrigerating machine, that is to say, arefrigerating apparatus in whichthe aforementioned drawback is removed by causirig'theliquid settlingatthe bottom of the evaporator to return automatically to the absorberunder the action of gravity. This is preferably effected by meansischarged back to the absorber,

also caus-;

647,733, and i Germany January 5, 1923..

of an overflow device connecting the evaporator with the. absorber in asuitable'manner. In the accompanying drawingione embodiment of myinvention isshown'diagrammatically by way of example.-

The refrigerant expelled from the generator-absorber 1 passes into thecondenser 2, is there liquefied and then flows from the condenser 2 intothe evaporator 3. During the subsequent cooling operation the pipe 5 isclosed and the gas formed in the evaporator 3 flows throughthe pipe 4back into the ab sorber 1. The two pipes or conduits may be combined ifdesired, but thereis no necessity for doing so. a Any absorbing liquidpresent in the liquor. passed into the evaporator 3 remains there and,therefore, towards the end of the evaporating process a residue ofliquor incapable of further evaporation is-left inthe evaporator 3. Thisresidue could be withdrawn from the evaporator by meansof a valve fittedat the bottom of'the evaporator or b evaporating it by heating theevaporator ext rnally but both methods as already mentioned arenotadmissible, the former because of the attendance re,-

quired and the necessity ofhaving a handcontrolled valve member, and thelatter because the apparatus is intended for cooling and not for heatingpurposes. I Q

Now, In invention relies upon the fact that the'lique ed cooling agenthas a lower specific gravity than the absorbing liquid and the residualliquor therefore has a correspondingly higher or specific. gravity. Theresidual liquor c'an'therefore be left in the evaporator for a'time andthe apparatus allowedto continue' in operation. As thecoolingagent is'lighter than the residual liquor, it does not mix with it toany'appreciable extent. In order to facilitate the separation of the twoliquors, however,-the bottom of the eva orator is formed as a sump 6where the residual liquor can settle, whilst the cooling agent forms alayer above it. The sump 6 is in open communication with the absorber 1by means of the by-pass 7.

The overflow level 11 of the by-pass 7 is a little above the normalhighest level of the liquor in the evaporator 3, when no absorbingliquid'is present therein. In proportion as the absorbing liquid isdistilled over into the evaporator the level of the column'of liquid inthe evaporator rises, and as soon as a I certain limit is passed, itsweight causes'a corresponding amoi nt of the bottom layer of n'ected upto the bottom of the evaporator, only the liquid contained in the sump6, that is to say the residual liquor consisting mainly of the absorbingliquid, will be returned to the absorber. The operation is entirelyautomatic, and no liquid is returned to the absorber, unless someabsorbing liquid gathers in the sump 6, and no attention is required toascertain if any absorbing liquid has collected in theevaporator and hasto be discharged therefrom.

The sensitivcncssflof the apparatus may be increased by reducing thecross-sectional area of the evaporator in the region 8 of the overflowlevel 11, so that only a small amount of excess liquid will suflice tocause the by-pass to act. The larger space 9 above the reduced part8 maywith advantage be used for separating the gaseous agent from the liquiddur ing the evaporating operation.

The intensity of discharge may be still furw v ther increased by givingthe pipe 7 a special siphon shape, the horizontal top portion and thedescending limb being narrower than the rising limb of the siphonwhereby, when the liquid in the evaporator rises above a certain level.a sudden evacuation .is effected. The quantity of liquid discharged fromthe evap orator 3 may be limited either by connecting the descendinglimb of the siphon pipe with the wider absorption pipe 4 so that thesiphoning action ceases when the liquid reaches a. certain level 14, orby providing an auxiliary or relief-pipe connecting the horizontal topportion of the siphon 7 with the evaporator i so that the siphon will bebroken at the top when the liquid in the evaporator falls to the level12.

From the foregoing, it is believed that the advantages and novelfeatures of my invention will be readily understood and therefore rfurther detailed description is deemed unnecessary. 4

In putting my invention into. practice I find that the preferredembodiment shown herein diagrammatically is the most practical andeflicient arrangement, but realizing that certain conditions willnecessarily vary when the invention is carried out in practice, I desireto emphasize the "fact that various changes in the details ofconstruction and arnecessity, in View of the object and scope of myinvention, for keeping closely to the particular mode of construction,connection and operation of the parts shown diagrammatically in thedrawing by way of example only.

What I'claim is: 1. An absorption refrigerating machine comprising incombination a generator-' absorber for vaporizing a'relatively volatilecooling agent from a relatively low volative absorbing medium,acondenser for condensing said vaporized cooling agent, an evaporatorarranged at a higher level. than said generator-absorber, saidevaporator comprising upper and lower portions, a constricted -pas sagebetween said upper and lower portion,

means for transferring condensate from said condenser to said upperportion, a suction pipe connecting saidupper portion with saidgenerator-absorber, and an unobstructed continuously open residue returnline from said lower portion to said suction pipe, said return linebeing capable of allowing the transfer from the bottom of said lowerportion of the contents in the lower part of said lower portion, on thelevel of the contents of the evaporator being in line with the saidconstricted passage. v

2. An absorption refrigerating machine comprising in combination agenerator- ,a sorber for vaporizing a relatively volatile cooling agentfrom a relatively low volative absorbing medium, a condenser forcondensing said vaporized cooling agent, an evaporator, saidevaporatorcomprising upper and lower portions, a constricted passagebetween said upper and lower portion, means for transferring condensatefrom said condenser to said upper portion, a suctionpipe connecting saidupper portion with the generatorabsorber, a sump in said lower portionand an unobstructed siphon connection from said sump to said suctionpipe.

In witness whereof I aflix my signature.

ELIAS- WIRTH-FREY.

